Hakry b



Julie 28, 1932. H B MASTERS 1,864,920

MILL

Filed March l5, 1929 INVENTOR ATTORNEYS,

Patented June 28, 1932 PATENT OFFICE HARRY B. MASTERS, OF KEOKUK, IOWA MILL Application mea March 13, 1929. serieu No. 346,646.

This. invention relates* to grinding Vman chines of the type known as hammer mills, and among other objects, the invention aims to increase the production of hammer mills and like machines particularly when used for grinding. grains and other products which tend tov cake orlform doughey masses which clogethe screen ofthe hammer mill.

In the accompanying drawing forming part of this application,

Fig. 1 is an elevation of a'hammer mill embodyingthe invention, parts being shown in vertical section so as to show the interiorY arrangement andl 16 Fig. 2 is a plan view of the three part suction'line which leads from the lower or dis charge side of the screen to the suction fan. The Agrinding of certain grain ley-products by commercial forms ofV hammer mills has S05-given a great dealfof trouble. The screen used should have a maximum mesh of -llg inch, and in someinstances could advantageously be smaller. When certain grain products'are ground,.the ground material willV 2- cake and completely fill the interstices'of the screen, preventing outflow of the groundmaterial and choking the machine with the material constantly being fed to the machine, necessitating shutting down the machine, takwing out'ithe screen and either cleaning it imf mediately or replacing it withV another," and clearing away the spilled material.

Effortstoobviateat least partial cakingV ingthrough the relatively small central bottom area of the screen, the sides of the screen having becomeclogged and entirely inelfeca tive;

from the others.

Accordingto the invention, the suction line Ais divided, into at least two and preferably three parts or lines, all preferably leading; to the usual suctionfan-mountedon the shaft ofthe hammer mill. This improvement has enabled the identical machine previously considered to be a failure, to handle continuously as high as 3600 lbs. per hour of the same material, an increase in productionof some 600%, without any extra expenditure of power or other disadvantages.

Referring particularly to the drawing, there is shown a hammer mill comprising a housing 5 having an intake Gthrough which the material to be ground is fed, a motor'- 65 driven shaft 7 to which the hammers 8 are connected, and a screen 9, semi-cylindrical in form. The parts described are all standard, but taken in combination with other elenr mentsto be described, form a part of the present invention.

Secured to thehammer mill is a casing '10 which serves as a sort of exhaust hood for the screen, beinoiopento the suction side of the usual fan not shown). In elfect, the casing 10 is the lower half of the'housing` of the mill, and provides a suction chamber at the base of the-machine. The casing 10' is divided by the re-entrant walls 11 into three parts, each providing asuction area comprehending roughly one-third of the total effective screen; area, and each being separate A suction pipe 12 leadsv from each'part of casing 10 to a fan intake or suction pipe 13 whose diameter is several85 times that offone of the pipes 12, thethreeV pipes preferably coming' together at onel point, as shown at'lfl. The three pipes 12 may be continued on the other side of the machine from-the fan, as shown in F ig; 2, and may have air` intake valves 15, which will increase vthe elfectiveness of the suction fan. Other air valves 16 maybe provided at various high points in casing 11 to prevent the material from accumulating at times against the upper part of thelcasing.

It will be understood that while Fig. 2 indicates that the fan suction line 13 isv more or less in the samey plane as the pipes 12, in practice Vthe suction line 13 is usuallyV- V100 shaped, being brought around to the suction fan (not shown) mounted on the shaft 7 of the hammer mill.

As improved results are obtained by using but two suction areas adjacent theiscreen, I believe I am entitled to claims broad enough to cover this less desirable arrangement, as well as the preferred construction shown in the drawing.

Obviously, the present invention is not restricted to the particular embodiment thereof herein shown and described.

What I claim is 1. In a mill, in combination, a screen; a power-driven shaft; disintegrating means revolved by the shaft adjacent said screen; a suction fan and a suction discharge hopper between the discharge side of the screen and thev fan, said suction discharge hopper being divided into a plurality of adjacent compartments into which the material ground above the screen directly discharges.

2. A hammer mill or the like comprising, in combinat-ion, a screen; a power-driven shaft; a multiplicity of hammers revolved by the shaft adjacent said screen; a suction fan; and a suction hood between the discharge side of the screen and thefan, said suction hood being divided into three substantially equal parts or areas into which the material ground above the screen directly discharges. Y

3. A hammer mill or the like comprising, in combination, a multiplicity of revolving hammers; a screen adjacent the path of movement of said hammers; a suction hood beneath the screen into whichcthe ground material is directly discharged, said hood having one or more re-entrant portions to provide Vtwo or more sharply` defined suction areas which together coinpr-ehend the entire screen; and separate pipes leading from said suction areas to a suctionline.

4. A hammer mill or the like comprising, in combination, a multiplicity .of revolving hammei's; a screen adjacent the path of movement of said hammers; a suction hood below the screen and covering the entire lower part thereof; said hood receiving the ground material directly from the screen and having one or more partition walls extending to the screen; said partition walls separating the suction hood into two or more suction areas; and a suction pipe leading from said areas so as to conduct away material sucked through the screen.

5. A hammer mill or the like comprising, in combination, a multiplicity of revolving hammers; a screen adjacent the path of movement of said hammers; av suction hood beneath the screen having one or more re-y entrant portions which extend in the direction of the shaft of thehammer mill to provide two or more sharply defined suction areas which together comprehend ,the entire 4*extending to the screen transversely thereof and separating the suction hood into two ormore suction areas; and a suction pipe lead-` ing from each of said suction areas so as to conduct away material sucked through the screen.

7 A hammer mill or the like comprising in combination, a multiplicity of revolving hammers; a cylindrical screen 'adjacent the path of movement of said hammers; a suction hood below and spaced from they screen covering the entire lower half thereof; said,

hood having two partition walls extending to the screen transversely thereof andproviding three sharply defined separatedsuction areas ony theV suction side of the screen;,the

ground material passing through the screen directly into the suction areas aforesaid; three suction pipes leading from the respective suction areas; and a suction linel of large diameter compared with said suction pipes having the longitudinal axis thereof lying in.

the same vertical plane with the middle suction pipe; the two outside suction pipes joining the suction line at the same point and being disposed symmetrically relative to the suction line.

8. A hammer mill or the like comprising, in combination, a multiplicity of revolving hammers; a cylindrical screen adjacent the path of movement of said hammer; a suction hood below and spaced from the screen and covering the entire lower half thereof; the ground material discharging directly into said hood; two partition walls inside the hood extending to the screen transversely thereof and providing three sharply dened separated suction pipes of equal area leading from the respective suction areas; and a suction line of large diameter compared with said suction pipes having the longitudinal axis thereof lying in the same vertical plane with the middle suction pipe; the suction line having a frusto-conical section where the middle suction pipe is joined to it and the two outside suction pipes joining the suction line at the frusto-conical section at diametrically opposit-e points.

9. In a hammer mill having revolving hammer means, a screen for separating fine from coarse material acted upon by said hammer means, and means for causing an air flow from within the mill outwardly through the screen to carry ground material therefrom,

the combination therewith of provisions for subdividing the screen into distinct areas and substantially equalizing the air iow through said areas.

10. A grinding mill having revolving hammers, a. screen outside of the hammers, a Chamber of which the screen forms one Wall, means for exhausting air from said chamber, and partition means Within the chamber dividing the same into separate passages each in separate communication with a dierent area of the screen.

In testimony, that I-claim the foregoing as my own, I have hereto affixed my signature.

HARRY B. MASTERS. 

